新疆极端降水时空特征及其对ENSO影响的响应研究

Spatial and Temporal Characteristics of Extreme Precipitation in Xinjiang and Its Response to ENSO

基于1961-2015年新疆地区51个气象站逐日降水资料和南方涛动指数资料,借助RclimDex模型,利用线性变率、距平分析、Mann-Kendall非参数检验等方法,分析过去55a新疆极端降水变化特征及其对ENSO影响的响应。研究表明:(1)1961-2015年新疆持续干燥日数以-3.9d·(10a)^-1的速率下降,除降水强度指数外,最大1日降水量、强降水量、总降水量和大雨日数都呈现显著上升趋势,且突变基本发生于1986年;(2)最大1日降水量、强降水量、总降水量和大雨日数都表现为“北多南少”的格局,其线性倾向率表现为北疆大部分站点正增长,且变化趋势明显,南疆少数站点呈负增长,且变化趋势较弱;(3)20世纪80年代以后ElNino/LaNina事件波动加剧,且ElNino事件发生强度大于LaNina事件。ElNino事件年对新疆产生增湿效应,冷季降水增加幅度大于暖季,空间上表现为北疆的塔城、阿勒泰、巴音布鲁克和南疆西部的喀什至和田一带年总降水明显偏多。

Based on the daily precipitation data and southern Oscillation Index data of 51 meteorological stations in Xinjiang from 1961 to 2015,we use the RclimDex model,linear variability,anomaly analysis,and Mann-Kendall nonparametric test to analyze the characteristics of extreme precipitation changes and their response to ENSO impacts in past 55 years in Xinjiang.The research shows that:(1)The number of continuous drying days in Xinjiang decreased by-3.9 d/10a in 1961-2015.Except the precipitation intensity index,the maximum 1-day precipitation,heavy precipitation,total precipitation and heavy rain days all showed a significant increase,and mutations basically occurred in 1986.(2)The maximum 1-day precipitation,heavy precipitation,total precipitation and heavy rain days all show the pattern of“northern more and south less”,and the linear tendency rate shows that most stations in northern Xinjiang are growing,and the trend is obvious.A few sites in southern Xinjiang showed negative growth and the trend is negligible.(3)The fluctuation of El Nino/La Nina events intensified after the 1980s,and the intensity of El Nino events was greater than that of La Nina.The El Nino event year has a humidifying effect on Xinjiang,and the precipitation in the cold season is greater than the warm season.The annual total precipitation in northern Xinjiang such as Tacheng,Altay,and Bayinbrook,and Kashgar-Hetian areas in the western part of southern Xinjiang is obviously higher.